Certain episodes of Treme seem to wear their ideological hearts on their sleeves, and this was one. You open with Desiree's mother's house getting torn down in a city mix-up; you have Davis throwing around phrases like "preservation through neglect"; you see housing projects torn down amid protest with the implication of a corrupt deal; you get protagonists like the Bernette family being harassed by police; you witness clueless developers trying to build a national jazz center while waiting for the other shoe to drop. (Perhaps the Ellis Marsalis Center for Music gives a clue to the writers' thinking?) Nothing involving anything "official" seems to work like it ought to.

But you still have music. Pianists and keyboard players feature prominently here, with Jonathan Batiste, Joe Krown and Tom McDermott making guest appearances, and we also hear some trad-jazz and classic R&B. To help recap the music, here's Josh Jackson of WBGO.

Patrick Jarenwattananon: The pianist Jonathan Batiste, another New York-based New Orleans product, is back on the show. We hear him with Delmond's "local" band, playing a tune called "Little Big Chief" by Leon "Kid Chocolate" Brown, who I'm not familiar with. Then we hear a Batiste original.

Josh Jackson: You may not know of Kid Chocolate, but you've heard him throughout the series: He plays the trumpet parts for the character Delmond Lambreaux. So that's actually him playing his own tune, "Little Big Chief," and Batiste's "Calm Before the Storm." Leon Brown is a New Orleans native and graduate of the New Orleans Center for Creative Arts, a magnet high school for the arts. I remember his early gigs at Donna's with drummer Bob French, where he showed a lot of promise.

PJ: Speaking of Batiste, Antoine has a gig this episode, too. Somehow he manages to get a substitute job at Preservation Hall, and we hear that band play what sounds like a traditional number, "That Bucket's Got a Hole in It."

JJ: It's a blues attributed to composer Clarence Williams, but that doesn't necessarily mean he wrote it. The origins of the song are obscure. Anecdotal evidence suggests that the pioneering improviser Buddy Bolden performed the song with his band, yet no recording exists (or any Bolden material, for that matter). Plenty of folks have recorded it, including Louis Armstrong. I'd guess that Hank Williams' version of "Bucket" is the most popular, leading many to believe it's a country tune.

PJ: We hear two intimate Christmas duo gigs this episode. The first one is where Annie and the pianist (whose name escapes me) play a classical-ish tune, and then the more characteristically New Orleans piece they "sneak in." Then there's the trumpet-piano duo at the end, when Nelson and his "mentor" are talking.

JJ: Joe Krown is regarded more for his Hammond organ playing, but we get to hear him in duo with Annie Tee at the Ogden Museum of Southern Art. They play a caprice from 19th-century composer Louis Moreau Gottschalk called "O Ma Charmante, Epargnez-Moi!" (Oh My Charmer, Spare Me), then follow with a Krown original, "All That & Then Some."

In the later scene, pianist Tom McDermott is playing with trumpeter Connie Jones, a former member of trombonist Jack Teagarden's band, at the Columns Hotel. They're playing McDermott's "Kermit's Rag," a song they recorded together on Creole Nocturne.

PJ: Annie's character gets fleshed out this episode. We learn she's signed with Lost Highway, an alt-country record label. We also meet her folks and learn that her mother had groomed her for a classical career. With her Bayou Cadillac band, she plays a song about Katrina, and then a more personal one, "Louisiana Christmas Day."

JJ: Viewers have had their fill of Katrina-related songs, but "Katrina" is both good and honest. You can find the original on the Red Stick Ramblers recording called Made in the Shade. (Once again, Annie's Bayou Cadillac is called The Red Stick Ramblers in real life.) By the time Annie and the band launch into "Louisiana Christmas Day," it seems that her mom (played by Isabella Rossellini) is maybe a tad more supportive. But can we now kill the overcooked stereotype that listening to classical music makes you so fusty? So annoying.

PJ: Who's the singer at Gigi's (LaDonna's bar) when her brother-in-law walks in? Can't say I recognize her from a glance.

JJ: That's Sharon Martin, a singer who plays mostly local gigs. She's belting out a great tune from Sugar Pie DeSanto, "Use What You Got." Carl LeBlanc, the guitarist in this scene, is a longtime collaborator with Ms. Martin.

PJ: Lots of Mardi Gras Indian chiefs this episode. Delmond visits the Montana family, of the Yellow Pocahontas. And Albert runs into other chiefs at the protest and at the costume shop: one identified as "Howard," and another as "Doucette."

JJ: We get to see many of the costumes of the late Big Chief Allison "Tootie" Montana, a master craftsman who masked for well over five decades. His output was prolific, and those suits are remarkable works of art. Albert Lambreaux meets Chief Howard Miller from the Creole Wild West again in this episode, as well as Alfred Doucette from the Flaming Arrow Warriors. Indians are very particular about the materials they use for their suits.

PJ: Finally, Davis' "tour" swings by Buddy Bolden's old haunts and this episode is titled "I Thought I Heard Buddy Bolden Say" — as we heard on the end credits. Any thoughts to that or any other background music?

JJ: Dr. John sings the version heard in the end title. Being a Christmas episode, we heard a few classic instrumentals for the season: Dexter Gordon's version of "The Christmas Song" and pianist Ellis Marsalis' take on "God Rest Ye Merry Gentlemen." We heard Philip Manuel singing "This Time of Year" on the radio at Janette's new restaurant, and New Birth Brass Band's "Jingle Bells" when LaDonna picks up the boys in her many-horsepower enclosed sleigh.